/* html设置 */
* {
    margin: 0;
    padding: 0;
}
/* body设置 */
body {
    width: 100%;
    background-color: #f9f7f7fe;
    font-family: Arial, sans-serif;
    margin: 0 auto;
    padding: 0;
    box-sizing: border-box;
}
/* header设置 */
header {
    width: 100%;
    background-color: #ffffff;
    height: 60px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: 0 3px 5px #ccc;
    box-sizing: border-box;
}
.header-container {
    max-width: 1920px;
    width: 1400px;
    margin: 0 auto;
    display: flex;
    align-items: center;
    justify-content: space-between;
    box-sizing: border-box;
}
/* header左侧logo */
.header-left {
    width: 10%;
    padding: 0 30px;
    display: flex;
    align-items: center;
}
/* header中间菜单 */
.header-center {
    width: 80%;
    text-align: center;
}
.header-center a {
    color: #000;
    text-decoration: none;
    padding: 10px 20px;
    margin: 0 10px;
    position: relative;
    transition: color 0.3s;
}
.header-center a:hover {
    color: #3498db;
}
.header-center a::after {
    content: '';
    position: absolute;
    left: 0;
    bottom: -5px;
    width: 100%;
    height: 5px;
    background-color: #3498db;
    opacity: 0;
    transition: opacity 0.3s;
}
.header-center a:hover::after {
    opacity: 1;
}
/* header右侧用户图像 */
.header-right {
    width: 10%;
}
.user-menu {
    position: relative;
    cursor: pointer;
}
.user-avatar {
    width: 30px;
    height: 30px;
    border-radius: 50%;
}
.dropdown-menu {
    display: none;
    position: absolute;
    top: 40px;
    background-color: white;
    box-shadow: 0 8px 10px rgba(0, 0, 0, 0.2);
    width: 100px;
    z-index: 1;
}
.dropdown-menu a {
    color: black;
    padding: 12px 16px;
    text-decoration: none;
    display: block;
}
.dropdown-menu a:hover {
    background-color: #f1f1f1;
}
/* main设置 */
main {
    width: 100%;
}
/* sidebar左侧侧边栏 */
.sidebar {
    width: 280px;
    height: 100%;
    background-color: #000000;
    position: fixed;
    margin-top: 0;
    padding-top: 60px;
}
.sidebar > ul {
    list-style: none;
    margin: 5px 20px 5px 20px;
    padding: 0;
}
.sidebar ul li {
    padding: 10px 0;
    cursor: pointer;
}

.sidebar ul li> a {
    font-size: 18px;
    font-weight: bold;
    color: #706f6f;
    text-decoration: none;
    display: block;
    text-align: left;
    padding: 5px 15px 5px 10px;
}
.sidebar ul li a:hover {
    color: #ffffff;
    background-color: #4f4e4e;
}
.sidebar ul .submenu {
    padding-left: 20px;
    display: none;
    list-style-type: none;
}
.sidebar ul .submenu li > a{
    font-size: 10px;
}
.sidebar ul a.expanded + .submenu {
    display: block; /* 当菜单项有.expanded类时，显示子菜单 */
}
/* main content内容 */
.content {
    margin-left: 280px;
    padding: 5px 10px;
}


